Material for organic electroluminescent device and organic electroluminescent device including the same

ABSTRACT

In Formula 1, Ar may be a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring, other than a substituted or unsubstituted phenanthryl group, and R1 to R18 may each independently be selected from hydrogen, deuterium, a cyano group, a fluorine group (e.g., fluorine), a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 30 carbon atoms for forming a ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority to and the benefit of JapanesePatent Application No. 2015-121597, filed on Jun. 17, 2015 in the JapanPatent Office, the entire content of which is incorporated herein byreference.

BACKGROUND

One or more aspects of embodiments of the present disclosure are relatedto a material for an organic electroluminescent device and an organicelectroluminescent device including the same.

Organic electroluminescent displays have been a recent focus ofdevelopment. Organic electroluminescent devices, which areself-luminescent devices used in organic electroluminescent displays,have also been a focus of development.

An example structure of an organic electroluminescent device may beobtained by sequentially laminating (or stacking) an anode, a holeinjection layer, a hole transport layer, an emission layer, an electrontransport layer, an electron injection layer, and a cathode. In such anorganic electroluminescent device, holes and electrons injected from theanode and the cathode, respectively, may recombine in the emission layerto generate excitons and thereby emit light via the transition (e.g.,radiative decay) of the generated excitons to a ground state.

In order to improve the emission lifetime of an organicelectroluminescent device, various compounds have been examined for usein each layer. For example, an amine compound has been used as a holetransport material of an organic electroluminescent device in therelated art.

SUMMARY

An organic electroluminescent device using an amine compound in therelated art as a hole transport material has insufficient emissionlifetime. Accordingly, a material capable of improving the emissionlifetime of an organic electroluminescent device is desired.

One or more aspects of embodiments of the present disclosure aredirected toward a novel and improved material for an organicelectroluminescent device that is capable of increasing the emissionlifetime of an organic electroluminescent device, and an organicelectroluminescent device including the same.

One or more aspects of embodiments of the present disclosure provide amaterial for an organic electroluminescent device, including a monoaminederivative represented by Formula 1:

In Formula 1, Ar may be a substituted or unsubstituted aryl group having6 to 30 carbon atoms for forming a ring, other than a substituted orunsubstituted phenanthryl group, and

R¹ to R¹⁸ may each independently be selected from hydrogen, deuterium, acyano group, a fluorine group (e.g., fluorine), a substituted orunsubstituted alkyl group having 1 to 10 carbon atoms, and a substitutedor unsubstituted aryl group having 6 to 30 carbon atoms for forming aring.

According to an aspect of the present disclosure, the emission lifetimeof an organic electroluminescent device may be increased.

In one embodiment, Ar may be an aryl group other than anaryl-substituted phenyl group.

According to an aspect of the present disclosure, the emission lifetimeof an organic electroluminescent device may be increased.

In one embodiment, Ar may be a substituted or unsubstituted phenylgroup, biphenyl group, terphenyl group, or quaterphenyl group.

According to an aspect of the present disclosure, the emission lifetimeof an organic electroluminescent device may be increased.

In one embodiment, Ar may be a substituted or unsubstituted naphthylgroup, naphthyl phenyl group, ternaphthyl group, binaphthyl group, ornaphthyl biphenyl group.

According to an aspect of the present disclosure, the emission lifetimeof an organic electroluminescent device may be increased.

One or more embodiments of the present disclosure provide an organicelectroluminescent device including the material for an organicelectroluminescent device in at least one layer.

In one embodiment of the present disclosure, an organicelectroluminescent device includes a first electrode, a second electrodeon the first electrode, and one or more organic layers between the firstelectrode and the second electrode, in which at least one layer selectedfrom the one or more organic layers includes the material for an organicelectroluminescent device.

According to an aspect of the present disclosure, the emission lifetimeof an organic electroluminescent device may be increased.

One or more embodiments of the present disclosure provide an organicelectroluminescent device including the material for an organicelectroluminescent device in at least one layer between an anode and anemission layer.

In one embodiment, an emission layer may be between the first electrodeand the second electrode, and the material for an organicelectroluminescent device may be included in at least one layer betweenthe first electrode and the emission layer.

In one embodiment, the emission layer may include a blue light emittingmaterial.

According to an aspect of the present disclosure, the emission lifetimeof an organic electroluminescent device may be increased.

In one embodiment, the organic layer including the material for anorganic electroluminescent device may be included in at least oneselected from a hole injection layer and a hole transport layer.

According to an aspect of the present disclosure, the emission lifetimeof an organic electroluminescent device may be increased.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing is included to enable further understanding ofthe present disclosure, and is incorporated in and constitutes a part ofthis specification. The drawing illustrates example embodiments of thepresent disclosure and, together with the description, serves to explainprinciples of the present disclosure. In the drawing:

The drawing is a schematic diagram showing an organic electroluminescentdevice according an embodiment of the present disclosure.

DETAILED DESCRIPTION

Example embodiments of the present disclosure will be described below inmore detail with reference to the accompanying drawing. In thespecification and drawing, elements having substantially the samefunction will be designated by the same reference numerals, and repeatedexplanations thereof will not be provided.

The thicknesses of layers, films, panels, regions, etc., may beexaggerated in the drawings for clarity. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening element(s) may also be present. In contrast, when an elementis referred to as being “directly on” another element, no interveningelements are present.

1. Components of Material for Organic Electroluminescent Device

The emission lifetime of an organic electroluminescent device may beincreased when the material for an organic electroluminescent device isused as a hole transport material. First, the components of the materialfor an organic electroluminescent device according to an embodiment ofthe present disclosure will be explained.

The material for an organic electroluminescent device according to anembodiment of the present disclosure may include a monoamine derivativerepresented by Formula 1:

In Formula 1,

Ar may be a substituted or unsubstituted aryl group having 6 to 30carbon atoms for forming a ring, other than a substituted orunsubstituted phenanthryl group, and R¹ to R¹⁸ may each independently beselected from hydrogen, deuterium, a cyano group, a fluorine group(e.g., fluorine), a substituted or unsubstituted alkyl group having 1 to10 carbon atoms, and a substituted or unsubstituted aryl group having 6to 30 carbon atoms for forming a ring. As used herein, “atoms forforming a ring” may refer to “ring-forming atoms”.

For example, in the monoamine derivative according to an embodiment ofthe present disclosure, the nitrogen atom of the monoamine derivativemay be combined (e.g., coupled) with carbon at position 9 of aphenanthryl group and with carbon at position 3 of a dibenzofuranylgroup.

In Formula 1, Ar may be a substituted or unsubstituted phenyl group,biphenyl group, terphenyl group, quaterphenyl group, naphthyl group,anthryl group, indenyl group, pyrenyl group, fluoranthenyl group,triphenylenyl group, perylenyl group, biphenylenyl group, naphthylphenyl group, naphthyl biphenyl group, ternaphthyl group, binaphthylphenyl group, or fluorenyl group.

In some embodiments, Ar may be an aryl group other than anaryl-substituted phenyl group. For example, Ar may be a substituted orunsubstituted naphthyl group, naphthyl phenyl group, ternaphthyl group,binaphthyl phenyl group, or naphthyl biphenyl group. In someembodiments, Ar may be a substituted or unsubstituted naphthyl phenylgroup.

In some embodiments, Ar may be a substituted or unsubstituted phenylgroup, biphenyl group, terphenyl group, or quaterphenyl group. However,embodiment of the present disclosure are not limited thereto.

Non-limiting examples of the Ar aryl group substituent may includedeuterium, a halogen atom (for example, fluorine, chlorine, etc.), analkyl group (for example, methyl, ethyl, propyl, butyl, etc.), analkenyl group (for example, vinyl, etc.), a silyl group (for example,trimethylsilyl, etc.), a cyano group, an alkoxy group (for example,methoxy, butoxy, etc.), a nitro group, a hydroxyl group, a thiol group,and an aryl group (for example, phenyl, naphthyl, terphenyl, fluorenyl,etc.), etc. The alkyl group may be selected from a linear alkyl group(for example, methyl, ethyl, propyl, butyl, octyl, decyl, pentadecyl,etc.), and a branched alkyl group (for example, t-butyl, etc.). Thesubstituent may be itself substituted with one or more selected from thesame substituents. In some embodiments, adjacent substituents maycombine (e.g., couple) with each other to form a ring.

In Formula 1, R₁ to R₁₈ may each independently be selected fromhydrogen, deuterium, a cyano group, a fluorine group (e.g., fluorine), asubstituted or unsubstituted alkyl group having 1 to 10 carbon atoms,and a substituted or unsubstituted aryl group having 6 to 30 carbonatoms for forming a ring. The substituted alkyl group having 1 to 10carbon atoms may be substituted with the same substituents available forthe Ar aryl group. In addition, the same substituted or unsubstitutedaryl groups having 6 to 30 carbon atoms available for the Ar aryl groupmay also be used for R₁ to R₁₈.

The monoamine derivative represented by Formula 1 according to anembodiment of the present disclosure may improve the emission lifetimeof an organic electroluminescent device when an emission layer includesa blue light emitting material.

In some embodiments, the material for an organic electroluminescentdevice according to an embodiment of the present disclosure may beincluded in one or more layers of the organic electroluminescent device.In some embodiments, the material for an organic electroluminescentdevice may be included in at least one layer between an emission layerand an anode of the organic electroluminescent device. For example, thematerial for an organic electroluminescent device may be included in oneselected from the hole transport layer and the hole injection layer ofthe organic electroluminescent device. However, embodiments of the layerincluding the material for an organic electroluminescent device are notlimited thereto. For example, the material for an organicelectroluminescent device may be included in any organic layer betweenthe anode and the cathode of an organic electroluminescent device.

An organic electroluminescent device using the material for an organicelectroluminescent device having the above-described components may havean improved emission lifetime, as described in the followingembodiments. The monoamine derivative represented by Formula 1 may be atleast one selected from Compounds 1 to 35. However, embodiments of themonoamine derivative are not limited thereto.

The monoamine derivative according to an embodiment of the presentdisclosure may be synthesized by Reactions 1 to 3. In some embodiments,the monoamine derivative according to an embodiment of the presentdisclosure may be synthesized by one selected from Reactions 1 to 3depending on the supply conditions of raw materials, etc.

In Reactions 1 to 3, X may be a halogen atom, etc., and the monoaminederivative according to an embodiment of the present disclosure may besynthesized via the coupling reaction of two compounds.

Embodiments of the synthesis of the monoamine derivative according to anembodiment of the present disclosure are not limited to the syntheticexamples of Reactions 1 to 3.

2. Organic Electroluminescent Device Using the Material for OrganicElectroluminescent Device

Hereinafter, an organic electroluminescent device using the material foran organic electroluminescent device according to an embodiment of thepresent disclosure will be described in more detail with reference tothe drawing. The drawing is a schematic cross-sectional view of anorganic electroluminescent device according to an embodiment of thepresent disclosure.

As shown in the drawing, an organic electroluminescent device 100according to an embodiment of the present disclosure may include asubstrate 110, a first electrode 120 on the substrate 110, a holeinjection layer 130 on the first electrode 120, a hole transport layer140 on the hole injection layer 130, an emission layer 150 on the holetransport layer 140, an electron transport layer 160 on the emissionlayer 150, an electron injection layer 170 on the electron transportlayer 160, and a second electrode 180 on the electron injection layer170.

Here, the monoamine derivative according to an embodiment of the presentdisclosure may be included in, for example, at least one selected fromthe hole injection layer 130 and the hole transport layer 140. In oneembodiment, the monoamine derivative according to an embodiment of thepresent disclosure may be included in both layers. In one embodiment,the monoamine derivative according to an embodiment of the presentdisclosure may be included in the hole transport layer 140 adjacent tothe emission layer 150.

Each organic thin layer between the first electrode 120 and the secondelectrode 180 of the organic electroluminescent device 100 may be formedby one or more suitable methods, such as an evaporation method.

The substrate 110 may be any suitable substrate available in the art foran organic electroluminescent device. For example, the substrate 110 maybe selected from a glass substrate, a semiconductor substrate, and atransparent plastic substrate.

The first electrode 120 may be on the substrate 110. The first electrode120 may be an anode and may be formed as a transmission type (e.g.,transmission) electrode using a metal, an alloy, a conductive compound,etc. having a high work function. The first electrode 120 may be formedusing, for example, transparent and highly conductive indium tin oxide(ITO), indium zinc oxide (IZO), tin oxide (SnO₂), zinc oxide (ZnO), etc.In some embodiments, the first electrode 120 may be formed as areflective type (e.g., reflective) electrode using magnesium (Mg),aluminum (Al), etc.

The hole injection layer 130 may be on the first electrode 120. The holeinjection layer 130 may facilitate easy injection of holes from thefirst electrode 120 and may be formed, for example, to a thickness ofabout 10 nm to about 150 nm.

The hole injection layer 130 may be on the first electrode 120. The holeinjection layer 130 may facilitate easy injection of holes from thefirst electrode 120 and may be formed, for example, to a thickness ofabout 10 nm to about 150 nm. The hole injection layer 130 may be formedusing the monoamine derivative according to an embodiment of the presentdisclosure or using any suitable material available in the art.Non-limiting examples of such material may include, for example,triphenylamine-containing polyether ketone (TPAPEK),4-isopropyl-4′-methyldiphenyliodoniumtetrakis (pentaflorophenyl)borate(PPBI),N,N′-diphenyl-N,N′-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4′-diamine(DNTPD), a phthalocyanine compound (such as copper phthalocyanine),4,4′,4″-tris(3-methylphenylamino) triphenylamine (m-MTDATA),N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB),4,4′,4″-tris{N,N-diamino}triphenylamine (TDATA), 4,4′,4″-tris(N,N-2-naphthylphenylamino)triphenylamine (2-TNATA),polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphorsulfonic acid (PANI/CSA),polyaniline/poly(4-styrenesulfonate (PANI/PSS), etc.

The hole transport layer 140 may be on the hole injection layer 130. Thehole transport layer 140 may include a hole transport material havingthe function of transporting holes and may be formed, for example, to athickness of about 10 nm to about 150 nm. The hole transport layer 140may be provided as a plurality of layers.

The hole transport layer 140 may include the monoamine derivativeaccording to an embodiment of the present disclosure. When the holeinjection layer 130 includes the monoamine derivative according to anembodiment of the present disclosure, the hole transport layer 140 mayinclude a suitable hole transport material available in the related art.Non-limiting examples of such hole transport material may include1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC), a carbazolederivative (such as N-phenyl carbazole and/or polyvinyl carbazole), N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1-biphenyl]-4,4′-diamine (TPD),4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA),N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB), etc.

The emission layer 150 may be provided on the hole transport layer 140.The emission layer 150 may emit light via fluorescence, phosphorescence,etc. and may be formed to a thickness of about 10 nm to about 60 nm. Thematerial of the emission layer 150 may be any suitable luminescentmaterial available in the related art (such as a fluoranthenederivative, a styryl derivative, a pyrene derivative, an arylacetylenederivative, a fluorene derivative, a perylene derivative, and/or achrysene derivative). In some embodiments, a styryl derivative, a pyrenederivative, a perylene derivative, and/or an anthracene derivative maybe used. For example, an anthracene derivative represented by Formula 2may be used as the material of the emission layer 150:

In the above Formula 2, each Ar₃ may be independently selected fromhydrogen, deuterium, a substituted or unsubstituted alkyl group having 1to 50 carbon atoms, a substituted or unsubstituted cycloalkyl grouphaving 3 to 50 carbon atoms for forming a ring, a substituted orunsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted orunsubstituted aralkyl group having 7 to 50 carbon atoms, a substitutedor unsubstituted aryloxy group having 6 to 50 carbon atoms for forming aring, a substituted or unsubstituted arylthio group having 6 to 50carbon atoms for forming a ring, a substituted or unsubstitutedalkoxycarbonyl group having 2 to 50 carbon atoms, a substituted orunsubstituted aryl group having 6 to 50 carbon atoms for forming a ring,a substituted or unsubstituted heteroaryl group having 5 to 50 carbonatoms for forming a ring, a substituted or unsubstituted silyl group, acarboxyl group, a halogen atom, a cyano group, a nitro group, and ahydroxyl group, and m may be an integer selected from 1 to 10.

For example, each Ar₃ may independently be a phenyl group, a biphenylgroup, a terphenyl group, a naphthyl group, a phenyl naphthyl group, anaphthyl phenyl group, an anthryl group, a phenanthryl group, afluorenyl group, an indenyl group, a pyrenyl group, an acetonaphthenylgroup, a fluoranthenyl group, a triphenylenyl group, a pyridyl group, afuranyl group, a pyranyl group, a thienyl group, a quinolyl group, anisoquinolyl group, a benzofuranyl group, a benzothienyl group, anindolyl group, a carbazolyl group, a benzoxazolyl group, abenzothiazolyl group, a quinoxalyl group, a benzoimidazolyl group, apyrazolyl group, a dibenzofuranyl group, a dibenzothienyl group, etc. Insome embodiments, each Ar₃ may independently be a phenyl group, abiphenyl group, a terphenyl group, a fluorenyl group, a carbazolylgroup, a dibenzofuranyl group, etc.

The compound represented by Formula 2 may be one selected from Compoundsa-1 to a-12. However, embodiments of the compound represented by Formula2 are not limited thereto.

The emission layer 150 may include a styryl derivative (such as1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (BCzVB),4′-(di-p-tolylamino)-4-[(di-p-tolylamino)styryl]stilbene (DPAVB), and/orN-(4-((E)-2-(6-((E)-4-(diphenylamino)styryl)naphthalene-2-yl)vinyl)phenyl)-N-phenylbenzeneamine (N-BDAVD)), aperylene derivative (such as 2,5,8,11-tetra-t-butylperylene (TBPe)), anda pyrene derivative (such as 1,1′-dipyrene, 1,4-dipyrenylbenzene and/or1,4-bis(N,N-diphenylamino)pyrene), but embodiments of the presentdisclosure are not limited thereto.

An electron transport layer 160 may be on the emission layer 150. Theelectron transport layer 160 may include an electron transport materialhaving the function of transporting electrons, and may have a thicknessof about 15 nm to about 50 nm.

The electron transport layer 160 may include an electron transportmaterial. Non-limiting examples of suitable electron transport materialsmay include tris(8-hydroxyquinolinato) aluminum (Alq3), a materialhaving a nitrogen-containing aromatic ring, etc. Non-limiting examplesof the material having a nitrogen-containing aromatic ring may include amaterial including a pyridine ring (such as1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene), a material including atriazine ring (such as2,4,6-tris(3′-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine), and amaterial including an imidazole derivative (such as2-(4-(N-phenylbenzoimidazolyl-1-ylphenyl)-9,10-dinaphthylanthracene)).

The electron injection layer 170 may be provided on the electrontransport layer 160. The electron injection layer 170 may facilitateeasy injection of electrons from the second electrode 180 and may have athickness of about 0.3 nm to about 9 nm. The electron injection layer170 may include any suitable material available in the art. For example,the electron injection layer 170 may include a Li complex (such aslithium-8-quinolinato (Liq) and/or lithium fluoride (LiF)), sodiumchloride (NaCl), cesium fluoride (CsF), lithium oxide (Li₂O), and/orbarium oxide (BaO).

In some embodiments, the second electrode 180 may be on the electroninjection layer 170. The second electrode 180 may be, for example, acathode, and may be formed as a reflective type (e.g., reflective)electrode using a metal, an alloy, a conductive compound, etc. having alow work function. The second electrode 180 may be formed using a metal(such as lithium (Li), magnesium (Mg), aluminum (Al), and/or calcium(Ca)), and/or a mixture of metals (such as aluminum-lithium (Al—Li),magnesium-indium (Mg—In), and/or magnesium-silver (Mg—Ag)). In someembodiments, the second electrode 180 may be formed as a transmissiontype electrode using ITO, IZO, etc.

Each of the above-mentioned layers may be formed by selecting anappropriate or suitable layer forming method (such as a vacuumevaporation method, a sputtering method, and/or various other coatingmethods) depending on the materials to be used.

The structure of the organic electroluminescent device 100 according toan embodiment of the present disclosure was explained as describedabove. The organic electroluminescent device 100 including the monoaminederivative according to an embodiment of the present disclosure may havean increased emission lifetime.

The structure of the organic electroluminescent device 100 according toan embodiment of the present disclosure is not limited to theabove-described embodiments. The organic electroluminescent device 100according to another embodiment of the present disclosure may be formedusing the structures of other organic electroluminescent devices in therelated art. For example, the organic electroluminescent device 100 mayomit one or more layers selected from the hole injection layer 130, theelectron transport layer 160, and the electron injection layer 170,and/or may include additional layers. In some embodiments, each layer ofthe organic electroluminescent device 100 may be formed as a singlelayer or as a plurality of layers.

In some embodiments, the organic electroluminescent device 100 mayinclude a hole blocking layer between the electron transport layer 160and the emission layer 150 to prevent or reduce diffusion of tripletexcitons and/or holes into the electron transport layer 160. In someembodiments, the hole blocking layer may be formed using, for example,an oxadiazole derivative, a triazole derivative, or a phenanthrolinederivative.

EXAMPLES

Hereinafter, the organic electroluminescent device according to anembodiment of the present disclosure will be explained in more detail byreferring to examples and comparative examples. However, the followingexamples are provided only for illustration of the organicelectroluminescent device according to embodiments of the presentdisclosure, and embodiments of the organic electroluminescent device arenot limited thereto.

[Synthesis of Monoamine Derivatives]

First, the synthetic method of the monoamine derivative according to anembodiment of the present disclosure will be described in more detail byreferring to Compounds 1, 4, 6, 7, and 34. The following syntheticmethods are only for illustration, and embodiments of the syntheticmethod of the monoamine derivative according to an embodiment of thepresent disclosure are not limited thereto.

(Synthesis of Compound 1)

Compound 1, a monoamine derivative according to an embodiment of thepresent disclosure, was synthesized according to Reaction 4:

Compound 1 was synthesized via reaction of arylamine Compound 51 withhalogenated aryl Compound 52 using a Pd-based catalyst to first produceintermediate Compound 53, as shown in Reaction 4.

A suspension (300 mL) of phenanthreneamine 51 (7.40 g, 38.3 mmol),bromodibenzofuran 52 (16.3 g, 19.9 mmol),diphenylphosphinoferrocenepalladium dichloride methylene chloridecomplex (PdCl₂(dppf)-CH₂Cl₂) (1.63 g, 1.99 mmol),diphenylphosphinoferrocene (dppf) (3.31 g, 5.97 mmol), and sodiumtert-butoxide (3.68 g, 3.83 mmol) was refluxed while stirring under anargon atmosphere for 8 hours. The reaction product was filtered usingFlorisil®, and the filtrate was concentrated. The residue was separatedby column chromatography to produce monoamine 53 (8.52 g, yield 62%).

Next, intermediate arylamine Compound 53 was reacted with halogenatedaryl Compound 44 using a Pd-based catalyst to synthesize the monoamineCompound 1 according to an embodiment of the present disclosure, asshown in Reaction 4.

For example, a xylene suspension (150 mL) of arylamine Compound 53 (5.16g, 14.3 mmol), bromobiphenyl Compound 44 (3.68 g, 15.8 mmol),tris(dibenzylideneacetone)bispalladiumchloroform addition product(Pd₂(dba)₃-CHCl₃) (446 mg, 0.432 mmol), sodium tert-butoxide (4.15 g,43.2 mmol), and tri-tert-butylphosphine (1.65 M toluene solution) (0.52mL, 0.86 mmol) was refluxed while stirring under an argon atmosphere for8 hours. The reaction product was filtered using Florisil®, and thefiltrate was concentrated. The residue was separated by columnchromatography to produce the monoamine derivative of Compound 1 (6.24g, yield 85%) according to an embodiment of the present disclosure.

The molecular weight of Compound 1 was measured using fast atombombardment-mass spectrometry (FAB-MS). The molecular weight was 511,coinciding with the calculated value of Compound 1 from the molecularformula of C₃₈H₂₅NO, and the structure of Compound 1 was therebyidentified.

(Synthesis of Compound 4)

Compound 4, a monoamine derivative according to an embodiment of thepresent disclosure, was synthesized according to Reaction 5:

Compound 4 was synthesized via reaction of arylamine Compound 51 withhalogenated aryl Compound 52 using a Pd-based catalyst to first produceintermediate Compound 53, as shown in Reaction 5. The synthetic methodof Compound 53 was substantially the same as that described for thesynthesis of Compound 1, and a detailed description thereof will not beprovided.

Next, intermediate arylamine Compound 53 was reacted with halogenatedaryl Compound 54 using a Pd-based catalyst to synthesize the monoamineCompound 4 according to an embodiment of the present disclosure, asshown in Reaction 5.

For example, a xylene suspension (150 mL) of arylamine Compound 53 (4.57g, 12.7 mmol), bromophenylnaphthalene Compound 54 (3.96 g, 14.0 mmol),tris(dibenzylideneacetone)bispalladium chloroform adduct (395 mg, 0.382mmol), sodium Pert-butoxide (3.67 g, 38.2 mmol), andtri-tert-butylphosphine (1.65 M toluene solution) (0.46 mL, 0.76 mmol)was refluxed while stirring under an argon atmosphere for 8 hours. Thereaction product was filtered using Florisil®, and the filtrate wasconcentrated. The residue was separated by column chromatography toproduce Compound 4 (6.45 g, yield 90%) according to an embodiment of thepresent disclosure.

The molecular weight of Compound 4 as measured by FAB-MS was 561, whichcoincides with the calculated value of Compound 4 from the molecularformula of C₄₂H₂₇NO, and the structure of Compound 4 was therebyidentified.

Chemical shift values of Compound 4 measured by ¹H-NMR (300 MHz, CDCl₃[ppm]) were 8.78 (d, 1H, J=8.3 Hz), 8.17 (dd, 1H, J=1.0, 8.2 Hz), 8.03(m, 1H), 7.89 (m, 1H), 7.80-7.86 (3H), 7.78 (s, 1H), 7.77 (d, 1H, J=8.4Hz), 7.56-7.72 (3H), 7.27-7.56 (13H), 7.20 (dd, 1H, J=2.0, 8.4 Hz).

(Synthesis of Compound 6)

Compound 6, a monoamine derivative according to an embodiment of thepresent disclosure, was synthesized according to Reaction 6.Substantially the same procedure as Reaction 5 was conducted, except forusing bromoterphenyl Compound 64 instead of bromophenylnaphthaleneCompound 54. The molecular weight of Compound 6 as measured by FAB-MSwas 623, which coincides with the calculated value of Compound 6 fromthe molecular formula of C₄₄H₂₉NO, and the structure of Compound 6 wasthereby identified.

(Synthesis of Compound 7)

Compound 7, a monoamine derivative according to an embodiment of thepresent disclosure, was synthesized according to Reaction 7.Substantially the same procedure as Reaction 5 was conducted, except forusing bromoterphenyl Compound 74 instead of using bromophenylnaphthaleneCompound 54. The molecular weight of Compound 7 as measured by FAB-MSwas 623, which coincides with the calculated value of Compound 7 fromthe molecular formula of C₄₄H₂₉NO, and the structure of Compound 7 wasthereby identified.

(Synthesis of Compound 34)

Compound 34, a monoamine derivative of according to an embodiment of thepresent disclosure, was synthesized according to Reaction 8.Substantially the same procedure as Reaction 5 was conducted, except forusing Compound 84 instead of using bromophenylnaphthalene Compound 54.The molecular weight of Compound 34 as measured by FAB-MS was 751, whichcoincides with the calculated value of Compound 34 from the molecularformula of C₅₇H₃₇NO, and the structure of Compound 34 was therebyidentified.

[Manufacture of Organic Electroluminescent Device Including AmineDerivative]

An organic electroluminescent device including the amine derivative as ahole transport material, according to an embodiment of the presentdisclosure, was manufactured using vacuum deposition according to thefollowing method:

Example 1

An ITO-glass substrate was patterned and washed in advance, and thensurface treated using ultraviolet rays and ozone (O₃). The thickness ofthe ITO layer (e.g., the first electrode) in the glass substrate wasabout 150 nm. After surface treatment, the substrate was washed andinjected into an evaporator for forming an organic layer, and a holeinjection layer, a hole transport layer (HTL), an emission layer, and anelectron transport layer were vacuum deposited one by one at a vacuumdegree of about 10⁻⁴ to about 10⁻⁵ Pa.

The material of the hole injection layer was4,4′,4″-tris(N,N-2-naphthylphenylamino) triphenylamine (2-TNATA), andthe thickness thereof was about 60 nm. The hole transport layer wasformed using Compound 1 to a thickness of about 30 nm. The emissionlayer included 9,10-di(2-naphthyl)anthracene (ADN) as a host materialand 2,5,8,11-tetra-t-butylperylene (TBP) as a dopant material, and wasformed to a thickness of about 25 nm. The doping amount of the dopantwas about 3% (volume/volume) with respect to the host material. Theelectron transport layer was formed using Alq₃ to a thickness of about25 nm.

The substrate was subsequently transferred to an evaporator for forminga metal layer, and an organic electroluminescent device was manufacturedby vacuum depositing an electron injection layer and a second electrodeat a vacuum degree of about 10⁻⁴ to about 10⁻⁵ Pa. The material of theelectron injection layer was LiF, and the thickness thereof was about 1nm. The material of the second electrode was Al, and the thicknessthereof was about 100 nm.

Example 2

An organic electroluminescent device was manufactured by conducting thesame procedure described in Example 1, except for forming the holetransport layer (HTL) using Compound 4.

Example 3

An organic electroluminescent device was manufactured by conducting thesame procedure described in Example 1, except for forming the holetransport layer (HTL) using Compound 6.

Example 4

An organic electroluminescent device was manufactured by conducting thesame procedure described in Example 1, except for forming the holetransport layer (HTL) using Compound 7.

Example 5

An organic electroluminescent device was manufactured by conducting thesame procedure described in Example 1, except for forming the holetransport layer (HTL) using Compound 34.

Comparative Example 1

An organic electroluminescent device was manufactured by conducting thesame procedure described in Example 1, except that the hole transportlayer (HTL) was formed using Comparative Compound C1. ComparativeCompound C1 differs from the monoamine derivative according to anembodiment of the present disclosure in that the nitrogen atom of amonoamine derivative is combined (e.g., coupled) with dibenzofuran via aphenylene group.

Comparative Example 2

An organic electroluminescent device was manufactured by conducting thesame procedure described in Example 1, except that the hole transportlayer (HTL) was formed using Comparative Compound C2. ComparativeCompound C2 differs from the monoamine derivative according to anembodiment of the present disclosure in that the nitrogen atom of amonoamine derivative is combined (e.g., coupled) with carbon at position2 of a phenanthrene group.

Comparative Example 3

An organic electroluminescent device was manufactured by conducting thesame procedure described in Example 1, except that the hole transportlayer (HTL) was formed using Comparative Compound C3. ComparativeCompound C3 differs from the monoamine derivative according to anembodiment of the present disclosure in that the nitrogen atom of amonoamine derivative is combined (e.g., coupled) with dibenzofuran via aphenylene group.

Evaluation Results

Evaluation results for the organic electroluminescent devices accordingto Examples 1 to 5 and Comparative Examples 1 to 3 are shown in Table 1.The emission properties of the organic electroluminescent devices thusmanufactured were evaluated using the C9920-11 Brightness LightDistribution Characteristics Measurement System of HAMAMATSU PhotonicsCo. In Table 1, the reported half life, measured at a constant currentdensity, indicates the time (LT50) elapsed between initial lightemission (at about 1,000 cd/m²) and the point when the luminescence ofthe organic electroluminescent device became half of the initialmeasurement. The results of Examples 1 to 5 and Comparative Examples 1to 3 are expressed as relative ratios, wherein the result of ComparativeExample 1 was normalized to a value of 1.

TABLE 1 Organic electroluminescent Half life (relative device Holetransport layer ratio) Example 1 Compound 1 1.7 Example 2 Compound 4 1.5Example 3 Compound 6 1.8 Example 4 Compound 7 1.6 Example 5 Compound 341.3 Comparative Example 1 Comparative 1 Compound C1 Comparative Example2 Comparative 0.8 Compound C2 Comparative Example 3 Comparative 0.8Compound C3

Referring to Table 1, the emission lifetimes of Examples 1 to 5including the monoamine derivative according to an embodiment of thepresent disclosure in the hole transport layer (HTL) were improvedcompared to those of Comparative Examples 1 to 3.

The organic electroluminescent devices according to Examples 1 to 5,which use monoamine derivatives in which the nitrogen atom of themonoamine derivative is directly linked to dibenzofuran, have improvedemission lifetimes compared to Comparative Example 1 (using ComparativeCompound C1) and Comparative Example 3 (using Comparative Compound C3),which have structures in which the nitrogen atom of the monoaminederivative is combined (e.g., coupled) to a dibenzofuran via a linkingphenylene group.

The organic electroluminescent devices according to Examples 1 to 5,which use monoamine derivatives in which the nitrogen atom of themonoamine derivative is coupled with the carbon at position 9 of aphenanthryl group, have improved emission lifetimes when compared toComparative Example 2 (using Comparative Compound C2), which has astructure in which the nitrogen atom of a monoamine derivative iscombined (e.g., coupled) with the carbon at position 2 of a phenanthrylgroup.

The emission lifetimes of the organic electroluminescent devicesaccording to Examples 1 to 4, which use monoamine derivatives accordingto Formula 1 in which Ar does not include a fluorenyl group, are furtherimproved when compared to the organic electroluminescent deviceaccording to Example 5, which uses a monoamine derivative including anAr fluorenyl group. The organic electroluminescent devices according toExamples 1, 3, and 4 use monoamine derivatives according to Formula 1 inwhich Ar is a biphenyl group or a terphenyl group, and have improvedemission lifetime compared to Example 2, which uses a monoaminederivative in which Ar is a phenyl naphthyl group.

As can be observed from the above results, when the monoamine derivativeaccording to an embodiment of the present disclosure has a structurerepresented by Formula 1, the emission lifetimes of organicelectroluminescent devices using the monoamine derivative may beimproved. Therefore, the monoamine derivative according to an embodimentof the present disclosure may be put to practical use as a material foran organic electroluminescent device in one or more suitable uses oforganic electroluminescent devices.

As described above, according to the present disclosure, the emissionlifetime of an organic electroluminescent device may be improved.

As used herein, expressions such as “at least one of”, “one of”, “atleast one selected from”, and “one selected from”, when preceding a listof elements, modify the entire list of elements and do not modify theindividual elements of the list. Further, the use of “may” whendescribing embodiments of the present disclosure refers to “one or moreembodiments of the present disclosure”.

In addition, as used herein, the terms “use”, “using”, and “used” may beconsidered synonymous with the terms “utilize”, “utilizing”, and“utilized”, respectively.

As used herein, the terms “substantially”, “about”, and similar termsare used as terms of approximation and not as terms of degree, and areintended to account for the inherent deviations in measured orcalculated values that would be recognized by those of ordinary skill inthe art.

Also, any numerical range recited herein is intended to include allsubranges of the same numerical precision subsumed within the recitedrange. For example, a range of “1.0 to 10.0” is intended to include allsubranges between (and including) the recited minimum value of 1.0 andthe recited maximum value of 10.0, that is, having a minimum value equalto or greater than 1.0 and a maximum value equal to or less than 10.0,such as, for example, 2.4 to 7.6. Any maximum numerical limitationrecited herein is intended to include all lower numerical limitationssubsumed therein and any minimum numerical limitation recited in thisspecification is intended to include all higher numerical limitationssubsumed therein. Accordingly, Applicant reserves the right to amendthis specification, including the claims, to expressly recite anysub-range subsumed within the ranges expressly recited herein.

While one or more example embodiments of the present disclosure havebeen described with reference to the drawing, it will be understood thatthe present disclosure should not be limited to these exampleembodiments, but various changes and modifications can be made by one ofordinary skill in the art within the spirit and scope of the presentdisclosure as defined by the following claims and equivalents thereof.

What is claimed is:
 1. A material for an organic electroluminescentdevice, the material comprising a monoamine represented by Formula 1:

wherein, in Formula 1, Ar is a substituted or unsubstituted aryl grouphaving 6 to 30 carbon atoms for forming a ring, other than a substitutedor unsubstituted phenanthryl group, and R¹ to R¹⁸ are each independentlyselected from hydrogen, deuterium, a cyano group, a fluorine group, asubstituted or unsubstituted alkyl group having 1 to 10 carbon atoms,and a substituted or unsubstituted aryl group having 6 to 30 carbonatoms for forming a ring.
 2. The material for an organicelectroluminescent device of claim 1, wherein Ar is an aryl group otherthan an aryl-substituted phenyl group.
 3. The material for an organicelectroluminescent device of claim 1, wherein Ar is a substituted orunsubstituted phenyl group, biphenyl group, terphenyl group, orquaterphenyl group.
 4. The material for an organic electroluminescentdevice of claim 1, wherein Ar is a substituted or unsubstituted naphthylgroup, naphthyl phenyl group, ternaphthyl group, binaphthyl group, ornaphthyl biphenyl group.
 5. The material for an organicelectroluminescent device of claim 1, wherein the monoamine representedby Formula 1 is at least one selected from Compounds 1 to 35:


6. An organic electroluminescent device, comprising: a first electrode;a second electrode on the first electrode; and one or more organiclayers between the first electrode and the second electrode, wherein atleast one layer selected from the one or more organic layers comprises amaterial for an organic electroluminescent device, the materialcomprising a monoamine represented by Formula 1:

wherein, in Formula 1, Ar is a substituted or unsubstituted aryl grouphaving 6 to 30 carbon atoms for forming a ring, other than a substitutedor unsubstituted phenanthryl group, and R¹ to R¹⁸ are each independentlyselected from hydrogen, deuterium, a cyano group, a fluorine group, asubstituted or unsubstituted alkyl group having 1 to 10 carbon atoms,and a substituted or unsubstituted aryl group having 6 to 30 carbonatoms for forming a ring.
 7. The organic electroluminescent device ofclaim 6, wherein an emission layer is between the first electrode andthe second electrode, and the material for an organic electroluminescentdevice is included in at least one layer between the first electrode andthe emission layer.
 8. The organic electroluminescent device of claim 7,wherein the emission layer comprises a blue light emitting material. 9.The organic electroluminescent device of claim 6, wherein the organiclayer comprising the material for an organic electroluminescent deviceis at least one selected from a hole injection layer and a holetransport layer.
 10. The organic electroluminescent device of claim 6,wherein Ar is an aryl group other than an aryl-substituted phenyl group.11. The organic electroluminescent device of claim 6, wherein Ar is asubstituted or unsubstituted phenyl group, biphenyl group, terphenylgroup, or quaterphenyl group.
 12. The organic electroluminescent deviceof claim 6, wherein Ar is a substituted or unsubstituted naphthyl group,naphthyl phenyl group, ternaphthyl group, binaphthyl group, or naphthylbiphenyl group.
 13. The organic electroluminescent device of claim 6,wherein the monoamine represented by Formula 1 is at least one selectedfrom Compounds 1 to 35: